A new state law will limit greatly the amount of opioids that doctors are allowed to prescribe patients suffering from acute pain.

Beginning July 1, doctors will be prohibited from prescribing more than a seven-day supply of opioid medication for patients in acute pain — pain from broken bones, bad backs, short illnesses and most surgeries, pain that's relatively short-term.

Doctors will not be allowed to write refills for the medications until the seven-day period has elapsed.

The idea behind the law: Fewer opioids will mean fewer chances to abuse them. Fewer chances for abuse will mean fewer overdose deaths, and fewer people getting involved in heroin. According to the U.S. Department of Health and Human Services, nearly 80 percent of Americans using heroin reported misusing prescription opioids prior to using heroin, according to research.

Dr. Nabil Sibai, an anesthesiologist who is chief of pain services at Henry Ford Hospital in Detroit, said that most patients with acute pain don't need to be on opioid medications for longer than 7 days. "There's a lot of data out there that shows that for most, at least 90 percent of acute pain episodes, (patients) are only going to require three to seven days of opioids," he said.

And the longer a patient is on opioids, the more likely he or she is to become dependent on them. "Exposure is a factor. ... If you only use a couple of days of opioids, you're less likely to become dependent or addicted. ... If you're provided more, you are likely to take more even if it's not needed."

Doctors have already been reducing the number of opioid prescriptions they write. Between 2013 and 2017, opioid prescriptions decreased 22 percent nationally, according to the American Medical Association.

In Michigan, they declined 10.7 percent between 2015 and 2017.

However, the number of overdose deaths continue to increase. About 42,000 people died from opioid overdoses in 2016, more than any previous year on record, according to the U.S. Department of Health and Human Services. Roughly 40 percent of those deaths involved a prescription opioid.

Between November 2016 and November 2017, about 73,000 people — including 2,749 in Michigan — died from drug overdoses, according to estimates from the U.S. Centers for Disease Control and Prevention. If recent trends hold true, the majority of those deaths will have been caused by opioids.

But as staggering as they may seem, the number of deaths by overdose is probably higher than the numbers reported by government agencies.

On Wednesday, "Public Health Reports," the journal of the Office of U.S. Surgeon General and U.S. Public Health Service, published an article saying that it's possible more than 70,000 overdose deaths went unreported across the nation — including Michigan — between 1999 and 2015.

The reason? Incomplete cause of death reporting on death certificates.